I’ve been training and working in and around the health and fitness field for a decade now. Most of it has been spent in the realm of personal training, but recently I’ve been working in the health promotion or wellness space. I get to help companies design and implement their health promotion strategy for their employees, and it’s given me a different perspective on some of my work as a trainer. One of those things is the Body Mass Index, or more commonly known as BMI.

Admittedly BMI on its own isn’t a great assessment, especially in a fitness setting. There are more accurate ways to measure body composition and body fat when working face to face with clients. The limitations to using BMI are obvious to anyone who knows a thing or two about health and fitness, but that’s not what I want to discuss. It’s about how complaining about the drawbacks of BMI makes fitness professionals look bad and how in conjunction with other biometric data (blood pressure, cholesterol, or blood sugar etc) that it can be helpful, not to mention how it can be applied when working with large populations (more on that later).

When I ran my gym a part of what I really missed (and I feel is missed by a lot of trainers) is a holistic view or complete perspective of the clients they are working with/assessing, and BMI can and should be a part of how that client is assessed. Hopefully you’ll see how setting aside your preconceived notions of BMI can actually allow you to use BMI for its intended use, instead of bitching and moaning about how it’s a terrible tool to assess clients with.

Click the link here to find out what your BMI is.

As trainers we so often focus only on getting people strong, helping them lose weight, and anywhere in between. Now that is awesome when you help your clients succeed and they meet their goals because that is what you are being paid to do, but having additional knowledge about biometric ranges and/or knowing a resource to send your clients to in order to meet all their health needs is invaluable. I’m not suggesting a trainer work outside their scope, but being able to have an intelligent conversation around these topics is a must, not to mention a way to differentiate yourself in a crowded industry. BMI should be a part of that conversation, and if you aren’t comfortable in addressing other health issues then I’d say it’s of the utmost importance to establish a network of professionals that can fill in those gaps for you.

Far too many trainers go out of their way to complain and list the myriad ways that the BMI fails as an assessment tool. While you may feel like Moses trotting down Mt. Sinai and delivering prophecy to clients about how the BMI sucks, I think it really just makes you seem like a whiny bitch, or a self-important asshole, you choose. Now I don’t mean to be harsh and I really don’t think you’re whiny or an asshole but nobody cares how smart you are, and more to the point explaining the fallacies of the BMI are not things your clients give a crap about. In fact I think it just gives them an out. I’ve heard enough “Johnny Biceps at my gym said the BMI isn’t a great tool to assess body fat and weight” while said person has a BMI of approximately 45, is diabetic and has high blood pressure, and is crushing donuts for breakfast regularly. Giving people fuel like “the BMI is a poor assessment tool” only enables them to use this as another way to not take ownership of their issues.   If you feel it’s important to share the drawbacks of BMI as an assessment tool I’d urge you to frame in it a conversation that still gives the tool merit, because it makes you seem less insecure.

One of the common complaints of BMI is it will inaccurately predict the body composition of the athletic population or those folks who are over muscular, and that is true. Talking about and debating this point is a great way to learn and understand different viewpoints, but that debate should be kept between professionals and not used as a way to show off how smart you are to your clients. If you want to be smart and valuable to your clients then know how to speak intelligently about BMI and how it ties to other biometric values (having that holistic view of your clients) and how that affects them. Regardless of whether your client is an athlete, general population, or over muscular, looking at more than one biometric value is revealing. If your client has a high BMI and no other risk factors, then maybe there isn’t anything to be concerned about. However, maybe they have a high BMI and high cholesterol, athlete or non-athlete; this is likely a cause for concern. The idea is to look at all the values then help your client make a decision about whether they need to discuss them further with their doctor, if they haven’t already, or what those values might actually mean to them. One singular value does not give us an accurate view of someone’s health, and it makes no difference whether they are an athlete or not, the more values they have that are out of range the more likely they are to encounter health issues.

Not to mention BMI was never designed to be an accurate assessment of body composition, but more a predictor of disease risk based on body composition. Restating the point, BMI is more about disease than body composition, so viewing it as a poor measure of body composition is misdirected because it was never intended to solely be about measuring body composition. It is simply a correlation that people with a BMI of >25 or >30 will more likely develop certain disease states than those that are in the 18.5-24.9 range. That does not however mean you 100% will develop those disease states if you are out of range, only that if you find yourself in those abnormal ranges that you are in fact more likely to develop them. Nor does it mean you can’t develop those disease states while inside that optimal range either.

So it comes down to a discussion of context. Since I’ve likely offended many of you with a biblical reference earlier I’ll do my best to alienate the rest of you with one of politics. You see when a member of a political party, democrat or republican, makes a statement the opposing party takes a small portion of that sound bite without giving the broader context of the statement. The same thing so often happens with BMI when we try and use it for something it wasn’t really designed for. By using BMI as the sole measure of body fat or body composition it’s like taking it as a sound bite from a much larger discussion. Viewing it in that context is at best confusing for clients and at worst dangerous if they go down the road of using it as a crutch to justify their weight.

BMI does in fact have significance as a clinical measure much like blood pressure or cholesterol does even though it isn’t as technical. When someone is diagnosed with high blood pressure we don’t’ tell them that it’s a poor assessment of how fast the blood moves in their arteries. We wouldn’t say that because that’s not what the test is designed to assess, blood pressure tests the pressure not speed of the blood in the arteries, even if the two might be related. BMI is no different and I think the issue that hangs us all up is the use of the classification for BMI, overweight, obese and so on. While these classifications are used as the frame of reference the focus of the tool is really on disease risk not body composition. You see most of us agree that a BMI of 45 means that person has a higher risk for disease and I’d bet they are also obese, either way we shouldn’t get hung up on the wording or the drawbacks of the assessment, but instead that the assessment tells us this person could be headed down the wrong path. Now our responsibility as fitness professionals is to find solutions to correct that measure and be supportive in the process by being a lightning rod of positivity not someone bent on showcasing our intelligence.

You still might wonder why context is important. Context matters because it is easy in this day and age to take things out of context. When we are limited to 140 characters or the length of a Facebook post oftentimes what’s shocking and attention grabbing is what gets the clicks, so we truncate and distill our message for the masses. When we do this we cut out valuable and necessary parts of the conversation and the broader context of the message gets missed as a result. Let’s not miss the broader context of BMI and how it can help us better understand what is going on with clients. Take a step back and look at how you can use the information provided from figuring someone’s BMI tie it into the other biometric ranges you have for them, and then help them get better.

As a last point I find that BMI is a tool that can help us look at the health of certain populations quickly and very inexpensively. In my day job, as I mentioned earlier, I help employers design and implement health promotion programs to administer to their employees, and there will likely never be a time that I meet face to face with each employee and assess their body composition. That would be costly and not to mention a waste of time, my time is better spent on designing larger initiatives to help them move the collective needle of their population’s health, and BMI can give me a glimpse in where I need to focus those efforts.

So using BMI as a way to judge the health of their population along with other risk factors gives me a snapshot of what the health of their population looks like, ultimately helping me to devise a plan to implement. It is one tool in the toolbox and does have value, so instead of focusing on its drawbacks I prefer to focus on how it can help me, because most of the time BMI is probably spot on and most (not all) of the people it categorizes as overweight or obese are likely just that no matter how terrible an assessment tool you think it is.